Method and system for packet communication employing path diversity

Abstract

Communication over lossy packet networks such as the Internet is hampered by limited bandwidth and packet loss. The present invention provides a path diversity transmission system for improving the quality of communication over a lossy packet network. The path diversity transmission system explicitly sends different subsets of packets over different paths, thereby enabling the end-to-end application to effectively see an average path behavior. Generally, seeing this average path behavior provides better performance than seeing the behavior of any individual random path. For example, the probability that all of the multiple paths are simultaneously congested is much less than the probability that a single path is congested. The resulting path diversity can provide a number of benefits, including enabling real-time multimedia communication and simplifying system design (e.g., error correction system design). Two exemplary architectures for achieving path diversity are described herein. The first architecture is based on source routing, and the second architecture is based on a relay infrastructure. The second architecture routes traffic through semi-intelligent nodes at strategic locations in the Internet, thereby providing a service of improved reliability while leveraging the infrastructure of the Internet.

1. A method for communicating information from a sender to a receiver through a network having a first path and a second path comprising:
 receiving an information stream;  
 generating at least a first subset of packets and a second subset of packets in response to the information stream;  
 establishing path diversity by sending the first subset of packets along the first path and sending the second subset of packets along the second path; and  
 dynamically changing the path diversity during transmission based on the communication conditions during a connection between a sender and a receiver.  
 
     
     
       2. The method of  claim 1  further comprising the steps of:
 receiving the first subset of packets;  
 receiving the second subset of packets;  
 recovering the information stream based on the first subset of packets, and second subset of packets, or both the first subset of packets and the second subset of packets.  
 
     
     
       3. The method of  claim 1  wherein the step of sending the first subset of packets along the first path includes
 identifying the first path by employing a path diversity service; and  
 
       wherein the step of sending the second subset of packets along the second path includes
 identifying the second path by employing a path diversity service.  
 
     
     
       4. The method of  claim 1  wherein the step of sending the first subset of packets along the first path and the step of sending the second subset of packets along the second path includes
 providing a source address, a destination address, a number of paths, the first stream and the second stream to a path diversity aware node;  
 the path diversity aware node identifying a first path and a second path, and  
 the path diversity aware node sending the first subset of packets along the first path and  
 sending the second subset of packets along the second path.  
 
     
     
       5. The method of  claim 1  further comprising:
 dynamically changing the number of paths based on the communication conditions between the sender and receiver.  
 
     
     
       6. The method of  claim 1  further comprising:
 dynamically changing at least one node of the first path or the second path based on the communication conditions between the sender and receiver.  
 
     
     
       7. The method of  claim 1  wherein the network includes
 a first relay having a first address and a second relay having a second address;  
 wherein the step of sending the first subset of packets along the first path includes sending the first subset of packets along the first relay by addressing the first subset of packets with the first address; and  
 wherein the step of sending the second subset of packets along the second path includes sending the second subset of packets along the second relay by addressing the second subset of packets with the second address.  
 
     
     
       8. The method of  claim 1  wherein the step of sending the first subset of packets along the first path includes
 specifying a first source route for the first subset of packets; and  
 sending the first subset of packets along the first source route; and wherein the step of sending the second subset of packets along the second path includes  
 specifying a second source route for the second subset of packets; and  
 sending the second subset of packets along the second source route.  
 
     
     
       9. The method of  claim 1  wherein the network is a cellular telephone network, a packet network, an Internet, an Intranet, a local area network, a wireless local area network, a wireless local area conforming to IEEE 802.11 specifications, or a local area network conforming to Bluetooth specifications. 
     
     
       10. The method of  claim 1  wherein the information is one of text information, file information, video information, audio information, voice information, multimedia information, control information, time sensitive information, time-sensitive video information, time-sensitive video information, and time-sensitive voice information, time-sensitive multi-media information, and time-sensitive control information. 
     
     
       11. A system for communicating information through a network comprising:
 a sender for receiving an information stream to be communicated;  
 a multiple stream generator for generating multiple streams that include at least a first stream and a second stream in response to the information stream; and  
 a path diversity unit coupled to the multiple stream generator for receiving the first stream and the second stream and for establishing path diversity by sending the first stream through a first path in the network and sending the second stream through a second path in the network;  
 wherein the path diversity unit dynamically changes the path diversity during transmission based on the communication conditions during a connection between the sender and a receiver.  
 
     
     
       12. The system of  claim 11  further comprising:
 a receiver for receiving the first stream and receiving the second stream; and  
 a recovery unit for recovering the information stream based on the first stream, the second stream, or both the first stream and the second stream.  
 
     
     
       13. The system of  claim 12  wherein the receiver can be one of a receiver that has no knowledge about path diversity transmission and a receiver that includes a mechanism for tracking the communication quality of each path and communicating the communication quality of each path to the sender for use in optimizing the transmission. 
     
     
       14. The system of  claim 11  wherein the network includes a first relay having a first address and a second relay having a second address; and
 wherein the path diversity unit sends the first stream through the first relay by addressing the first stream with the first address; and sends the second stream through the second relay by addressing the second stream with the second address.  
 
     
     
       15. The system of  claim 11  wherein the sender includes
 an IP source router for specifying a first source route for the first stream, sending the first stream along the first source route, specifying a second source route for the second stream, and sending the second stream along the second source route.  
 
     
     
       16. The system of  claim 15  wherein the first source route is one of a loose source route that specifies a subset of nodes of the route and a strict source route that specifies all the nodes of the route; and wherein the second source route is one of a loose source route that specifies a subset of nodes of the route and a strict source route that specifies all the nodes of the route. 
     
     
       17. The system of  claim 11  wherein the network is a cellular telephone network, a packet network, the Internet, an Intranet, a local area network, a wireless local area network, a wireless local area conforming to IEEE 802.11 specifications, or a local area network conforming to the Bluetooth specifications. 
     
     
       18. The system of  claim 11  wherein the information is one of text information, file information, video information, audio information, voice information, multimedia information, control information, time-sensitive information, time-sensitive video information, time-sensitive video information, time-sensitive voice information, time-sensitive multi-media information, and time-sensitive control information. 
     
     
       19. The system of  claim 11  wherein the path diversity unit performs sending the first stream and the second stream through a first path and second path, respectively, by employing a path diversity aware node. 
     
     
       20. The system of  claim 11  wherein the path diversity unit specifies one of all nodes to be traversed and a subset of nodes to be traversed; and 
       wherein the subset of nodes can include one of at least one node in the beginning portion of the path, at least one node in the middle portion of the path, and at least one node in the end portion of the path. 
     
     
       21. The system of  claim 11  wherein the path diversity unit dynamically changes at least one node of the first path or second path during transmission in response to communication conditions between the sender and receiver. 
     
     
       22. The system of  claim 11  wherein the path diversity unit dynamically changes the number of paths employed during transmission in response to communication conditions between the sender and receiver. 
     
     
       23. The system of  claim 11  having multiple paths and multiple streams; wherein the path diversity unit assigns streams to paths in one of a deterministic fashion, random fashion, and pseudo-random fashion. 
     
     
       24. The system of  claim 11  further comprising:
 at least two different Internet Service Providers for connecting the sender to the network;  
 wherein the path diversity unit achieves path diversity by sending different streams to each of the different Internet Service Providers.  
 
     
     
       25. The system of  claim 11  further comprising:
 at least two different connection technologies for connecting the sender to the network;  
 wherein the path diversity unit achieves path diversity by sending a first stream through a first connection technology and sending a second stream through a different connection technology.  
 
     
     
       26. The system of  claim 11  wherein the different connection technologies include a satellite link, a wired link, a wireless link, and a cellular link. 
     
     
       27. The method of  claim 11  allowing an application to specify to one of a sender and a path diversity service at least one QoS parameter for each substream of packets. 
     
     
       28. The system of  claim 11  wherein the sender applies one of
 Forward Error Correction Coding to a packet sent along one of the paths and across packets sent along multiple paths and  
 interleaving to a packet sent along one of the paths and across packets sent along multiple paths.  
 
     
     
       29. The system of  claim 11  wherein the first stream and the second stream are dependent on each other; and wherein the sender applies interleaving and Forward Error Correction Coding to a packet sent along one of the paths and across packets sent along multiple paths. 
     
     
       30. The system of  claim 11  wherein the sender employs path-hopping path diversity. 
     
     
       31. The system of  claim 30  wherein the path diversity unit assigns streams to paths in one of a deterministic fashion, random fashion, and pseudo-random fashion. 
     
     
       32. A system for communicating information through a network comprising:
 a sender for receiving an information stream to be communicated;  
 a multiple stream generator for generating multiple streams that include at least a first stream and a second stream in response to the information stream; and  
 a path diversity unit coupled to the multiple stream generator for receiving the first stream and the second stream and for establishing path diversity by sending the first stream through a first path in the network and sending the second stream through a second path in the network, wherein the path diversity unit performs path selection by employing a path diversity service that selects a path in response to path parameters; and  
 wherein the path diversity unit dynamically changes the path diversity during transmission based on the communication conditions during a connection between the sender and a receiver.  
 
     
     
       33. The system of  claim 32  wherein the path parameters can include a source address, destination address, number of paths, and quality of service requirements for each path; and wherein the quality of service requirements for each path can include bandwidth, delay and packet loss. 
     
     
       34. A method for communicating information from a sender to a receiver through a network having a first path and a second path comprising:
 receiving an information stream;  
 generating at least a first subset of packets and a second subset of packets in response to the information stream;  
 establishing path diversity by 
 sending the first subset of packets along the first path by specifying a first source route for the first subset of packets and sending the first subset of packets along the first source route; and  
 sending the second subset of packets along the second path by specifying a second source route for the second subset of packets and sending the second subset of packets along the second source route,  
 wherein the first source route is one of a loose source route that specifies a subset of nodes of the route and a strict source route that specifies all the nodes of the route; and wherein the second source route is one of a loose source route that specifies a subset of nodes of the route and a strict source route that specifies all the nodes of the route,  
 and  
 
 dynamically changing the path diversity during transmission based on the communication conditions during a connection between a sender and a receiver.